AddLinkTag() or AddImageSrc()

Many sites (notably Facebook) use the image specified in a link tag of type image_src as the graphic displayed when someone posts a link to the site. Unfortunately, there is no way to work with this. HTTPRequestHandler has the code for it (it is how AddFavicon() works!) but that code is not accessible to an eSpace. Either the code should be added, or an AddImageSrc() function could be added, because this functionality is critical to having Agile Platform apps look good when linked to on Facebook and other sites.